Hello good people of this forum!
... and happy new year 
I have one big problem, and one smaller one.
My master project is a remote control system of my summer cabin. With remote control on relays on for example the heating cables in the water pipes, temperature sensors and power outage warning. That I have mostly under control. But the thing that I cannot for the love of me get to work, is the GSM communication!
I have an Arduino Uno R3 as the "main" board, and I am using this (link) GSM shield.
http://tronixlabs.com/arduino/shields/gsm/sim900-gsm-shield-for-arduino-australia/
The code I am using is posted below.
Here is a downloadlink to the GSM library I am using, for convenience.
http://www.gsmlib.org/download.html
Big problem:
Now, as stated in the header, this code sends an SMS in void setup() to say that it has started correctly. I receive this SMS every time is starts, so thats ok, but it does not display any SMS that I send to the arduino.
The wierd thing is that I had this exact code working flawlessly a few days ago, but one day for no aparent reason stopped displaying any incoming sms.
In the GSM library Im using there is a file called GSM.h, in there I was able to enable debug mode so that is prints all AT commands to the serial monitor. It does not even see that there is a new "UNREAD" sms.
My knowledge of arduino into a corner on this one. It might be something obvious, but Im not seeing it.
Small problem:
While I had the aforementioned code working, I was woking on a way to get the char sms_text converted into an interger to use as a switch() for the I2C relayshield Im using. However, before I could complete it, the "big problem" came.
If you bright minds would look at it I would appreciate that alot!
Just for the sake of completeness Im posting the "main" code that controls the relay8 relayboard I have and the temp sensors. There are some Norwegian strings in there, but I hope you can manage.
I built this code from some online tutorials and some from own knowledge. I built it to work with input from serial thinking I could convert it to input from GSM once I got that up and running.
Thanks in advance, any help is greatly appreciated!
Arduino GSM.ino (1.1 KB)
Arduino GSM textfile.txt (1.15 KB)
GSM_char_to_int.ino (1.27 KB)
GSM_char_to_int_textfile.txt (1.28 KB)
Main code.ino (6.3 KB)
Main code textfile.txt (6.59 KB)